Auris- I think you have made good choices and you will be happy with the 7.0 and the 9.0 on the Futura 122.
A sail has a range of about 5 knots in which it feels best. So you will probably use the 9.0 from 10-15 knots, and you will use the 7.0 from 15-20 knots. However, I agree with Ken that when it is blowing more than 20 knots your 7.0 will probably be too big. A 5.5 would be more appropriate for 20-25 knots.
The link below tells you the ideal sail size for your weight and different wind strengths.
http://www.vims.edu/general/sailpadd...Calculator.xls